计算(a-1分之a减a²-1分之a²)÷(1减a+1分之1）+1
问题描述：
计算(a-1分之a减a²-1分之a²)÷(1减a+1分之1）+1
答
(a/a-1 - a²/a²-1)÷(1 - 1/a+1）+1
=a(a+1)- a²/(a+1)(a-1) ÷ a/a+1 +1
=a/(a+1)(a-1) × a+1/a + 1
=1/a-1 + 1
=a/a-1